This invention relates to a series of novel diphenyl ether compounds which inhibit monoamine re-uptake. In particular compounds of the present invention exhibit activity as selective serotonin re-uptake inhibitors (SSRIs) and have utility therefore in a variety of therapeutic areas. More notably the compounds of the present invention are useful in the treatment or prevention of a variety of disorders, including those in which the regulation of monoamine transporter function is implicated, such as depression, attention deficit hyperactivity disorder, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse disorders and sexual dysfunction including premature ejaculation, and to pharmaceutical formulations containing such compounds.
According to a first aspect, the invention provides a compound of general formula (I), or pharmaceutically acceptable salts, solvates or polymorphs thereof; 
wherein;
R1 and R2, which may be the same or different, are hydrogen, C1-C6alkyl, (CH2)m(C3-C6cycloalkyl) wherein m=0, 1, 2 or 3, or R1 and R2 together with the nitrogen to which they are attached form an azetidine ring;
each R3 is independently CF3, OCF3, C1-4alkylthio or C1-C4alkoxy;
n is 1, 2 or 3; and
R4 and R5, which may be the same or different, are:
Axe2x80x94X, wherein A=xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94(CH2)pxe2x80x94 where p is 0, 1 or 2; X is hydrogen, F, Cl, Br, I, CONR6R7, SO2NR6R7, SO2NHC(xe2x95x90O)R6, OH, C1-4alkoxy, NR8SO2R9, NO2, NR6R11, CN, CO2R10, CHO, SR10, S(O)R9 or SO2R10; R6, R7, R8 and R10 which may be the same or different, are hydrogen or C1-6alkyl optionally substituted independently by one or more R12; R9 is C1-6 alkyl optionally substituted independently by one or more R12; R11 is hydrogen, C1-6 alkyl optionally substituted independently by one or more R12, C(O)R6, CO2R9, C(O)NHR6 or SO2NR6R7; R12 is F (preferably up to 3), OH, CO2H, C3-6cycloalkyl, NH2, CONH2, C1-6alkoxy, C1-6alkoxycarbonyl or a 5- or 6-membered heterocyclic ring containing 1, 2 or 3 heteroatoms selected from N, S and O optionally substituted independently by one or more R13; or R6 and R7, together with the nitrogen to which they are attached, form a 4-, 5- or 6-membered heterocyclic ring optionally substituted independently by one or more R13; or
a 5- or 6-membered heterocyclic ring containing 1, 2 or 3 heteroatoms selected from N, S and O optionally substituted independently by one or more R13;
wherein R13 is hydroxy, C1-C4alkoxy, F, C1-C6alkyl, haloalkyl, haloalkoxy, xe2x80x94NH2, xe2x80x94NH(C1-C6alkyl) or xe2x80x94N(C1-C6alkyl)2; and wherein when R1 and R2 are methyl, R4 and R5 are hydrogen and n is 1, R3 is not a xe2x80x94SMe group para to the ether linkage linking rings A and B.
Unless otherwise indicated, any alkyl group may be straight or branched and is of 1 to 6 carbon atoms, preferably 1 to 4 and particularly 1 to 3 carbon atoms.
Unless otherwise indicated, any heterocyclyl group contains 5 to 7 ring-atoms up to 4 of which may be hetero-atoms such as nitrogen, oxygen and sulfur, and may be saturated, unsaturated or aromatic. Examples of heterocyclyl groups are furyl, thienyl, pyrrolyl, pyrrolinyl, pyrrolidinyl, dioxolanyl, oxazolyl, thiazolyl, imidazolyl, imidazolinyl, imidazolidinyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, pyranyl, pyridinyl, piperidinyl, dioxanyl, morpholino, dithianyl, thiomorpholino, pyridazinyl, pyrimidinyl, pyrazinyl, piperazinyl, sulfolanyl, tetrazolyl, triazinyl, azepinyl, oxazepinyl, thiazepinyl, diazepinyl and thiazolinyl. In addition, the term heterocyclyl includes fused heterocyclyl groups, for example benzimidazolyl, benzoxazolyl, imidazopyridinyl, benzoxazinyl, benzothiazinyl, oxazolopyridinyl, quinolinyl, quinazolinyl, quinoxalinyl, dihydroquinazolinyl, benzothiazolyl, phthalimido, benzofuranyl, benzodiazepinyl, indolyl and isoindolyl. The term heterocyclic should be similarly construed.
Preferably R1 and R2, which may be the same or different, are hydrogen or C1-C6alkyl. More preferably hydrogen or methyl.
Preferably each R3 is independently xe2x80x94CF3, xe2x80x94OCF3, methylthio, ethylthio or methoxy.
Preferably at least one R3 is para to the ether linkage linking ring A and B.
Preferably at least one R3 is methylthio.
Preferably R4 and R5, which may be the same or different, are xe2x80x94(CH2)pxe2x80x94X, where p is 0, 1 or 2 (preferably 0 or 1); X is hydrogen, hydroxy, CONR6R7, SO2NR6R7, NR8SO2R9, SR10, SOR9 or SO2R10 wherein R6, R7, R8, R9 and R10 are as defined in the first aspect, or a 5- or 6-membered heterocyclic ring containing 1, 2 or 3 heteroatoms selected from N, S and O (preferably oxadiazolyl, triazolyl, imidazolyl, oxazolyl, pyrazolyl, pyridinyl or pyrimidinyl).
More preferably R4 and R5, which may be the same or different, are: xe2x80x94(CH2)pxe2x80x94X, where p is 0 or 1; X is hydrogen, hydroxy, CONR6R7, SO2NR6R7 or NR8SO2R9; wherein R6 and R7, which may be the same or different, are hydrogen or C1,-C3alkyl optionally substituted by hydroxy, xe2x80x94CONH2 or C1-C3alkoxy (preferably methoxy); R8 is hydrogen, hydroxyethyl or methyl; or R9 is methyl, ethyl, isopropyl, trifluoromethyl or methoxyethyl; or triazolyl, imidazolyl or pyrazolyl.
More preferably still R4 and R5 are not both hydrogen. More preferably still R4 is hydrogen.
Preferably R6 and R7, which may be the same or different, are hydrogen, C1-C3alkyl optionally substituted by hydroxy, xe2x80x94CONH2 or C1-C3alkoxy (preferably methoxy). More preferably R6 and R7, which may be the same or different, are hydrogen or methyl, more preferably still hydrogen.
When present, R12 is preferably oxadiazolyl, triazolyl, imidazolyl, oxazolyl, pyrazolyl, pyridinyl or pyrimidinyl. More preferably triazolyl, imidazolyl or pyrazolyl.
In the case where R6 and R7, together with the nitrogen to which they are attached, form a heterocyclic ring, preferred rings are pyrrolidine or piperidine rings each of which may be substituted by OH or CONH2 or a morpholine ring which may be substituted by CONH2.
Preferably R11 is hydrogen or C1-6 alkyl.
Preferably R8 is hydrogen, hydroxyethyl or methyl. More preferably hydrogen.
Preferably R9 is methyl, ethyl, isopropyl, trifluoromethyl or methoxyethyl. More preferably methyl or ethyl (preferably methyl).
Preferably R10 is methyl or ethyl.
Preferably p is 1 or 0, more preferably 0.
Preferably
R1 and R2, which may be the same or different, are hydrogen or methyl; at least one R3 is para to the ether linkage and is CF3, OCF3, methylthio, ethylthio or methoxy; and
R4 and R5, which may be the same or different, are (CH2)pxe2x80x94X, where p is 0 or 1; X is hydrogen, hydroxy, CONR6R7, SO2NR6R7, NR8SO2R9, SR10, SOR9 or SO2R10 and wherein R6 and R7, which may be the same or different, are hydrogen, C1-C3alkyl optionally substituted by hydroxy, xe2x80x94CONH2 or C1-C3alkoxy (preferably methoxy); or R6 and R7, together with the nitrogen to which they are attached, may form a morpholine, pyrrolidine or piperidine ring each of which may be substituted by OH or CONH2; R8 is hydrogen, hydroxyethyl or methyl (preferably hydrogen); R9 is methyl, ethyl, isopropyl, trifluoromethyl or methoxyethyl; and R10 is methyl or ethyl; or an oxadiazolyl, triazolyl, imidazolyl, oxazolyl, pyrazolyl, pyridinyl or pyrimidinyl group.
More preferably R1 and R2, which may be the same or different, are hydrogen or methyl; at least one R3 is para to the ether linkage and is CF3, OCF3, methylthio, ethylthio or methoxy, and at least one R3 is methylthio or ethylthio; and
R4 and R5, which may be the same or different, are xe2x80x94(CH2)pxe2x80x94X, where p is 0 or 1; X is hydrogen, hydroxy, CONR6R7, SO2NR6R7 or NR8SO2R9; wherein R6 and R7, which may be the same or different, are hydrogen, C1-C3alkyl optionally substituted by hydroxy, xe2x80x94CONH2 or C1-C3alkoxy (preferably methoxy); R8 is hydrogen, hydroxyethyl or methyl; R9 is methyl, ethyl, isopropyl, trifluoromethyl or methoxyethyl; or triazolyl, imidazolyl or pyrazolyl.
More preferably still R1 and R2, which may be the same or different, are hydrogen or methyl; at least one R3 is para to the ether linkage and is CF3, OCF3, methylthio or methoxy, and at least one R3 is methylthio;
R4 is hydrogen, and
R5 is xe2x80x94(CH2)pxe2x80x94X, where p is 0 or 1; X is hydrogen, hydroxy, CONR6R7, SO2NR6R7 or NR8SO2R9; wherein R6 and R7, which may be the same or different, are hydrogen, C1-C3alkyl optionally substituted by hydroxy, xe2x80x94CONH2 or C1-C3alkoxy (preferably methoxy); R8 is hydrogen, hydroxyethyl or methyl; R9 is methyl, ethyl, isopropyl, trifluoromethyl or methoxyethyl; or triazolyl, imidazolyl or pyrazolyl.
More preferably still R4 and R5 are not both hydrogen.
For the avoidance of doubt, unless otherwise indicated, the term substituted means substituted by one or more defined groups. In the case where groups may be selected from a number of alternatives groups, the selected groups may be the same or different.
For the avoidance of doubt, the term independently means that where more than one substituent is selected from a number of possible substituents, those substituents may be the same or different.
Preferred compounds of formula (I) include:
3-[(dimethylamino)methyl]-4-[4-(methylsulfanyl)phenoxy]benzenesulfonamide;
3-[(dimethylamino)methyl]-N-methyl-4-[4-(trifluoromethyl)phenoxy]benzenesulfonamide;
3-[(dimethylamino)methyl]-4-[4-(trifluoromethoxy)phenoxy]benzenesulfonamide;
3-[(dimethylamino)methyl]-N-[(2R)-2-hydroxypropyl]-4-[4-(methylsulfanyl)-phenoxy]benzenesulfonamide;
3-[(dimethylamino)methyl]-N-[(1S)-2-hydroxy-1-methylethyl]-4-[4-(methylsulfanyl)-phenoxy]benzenesulfonamide;
3-[(dimethylamino)methyl]-N-(2-hydroxyethyl)-4-[4-(methylsulfanyl)phenoxy]-benzenesulfonamide;
3-[(dimethylamino)methyl]-4-[4-(methylsulfanyl)phenoxy]benzonitrile;
3-[(dimethylamino)methyl]-4-[4-(methylsulfanyl)phenoxy]benzamide;
3-[(dimethylamino)methyl]-4-[4-(trifluoromethoxy)phenoxy]benzamide;
3-[(methylamino)methyl]-4-[4-(methylsulfanyl)phenoxy]benzamide;
N-{3-[(dimethylamino)methyl]-4-[4-(trifluoromethyl)phenoxy]phenyl}-methanesulfonamide;
4-[3-methoxy-4-(methylsulfanyl)phenoxy]-3-[(methylamino)methyl]benzamide;
N-methyl-3-[(methylamino)methyl]-4-[4-(methylsulfanyl)phenoxy]benzamide;
3-[(dimethylamino)methyl]-4-[3-methoxy-4-(methylsulfanyl)phenoxy]-benzamide;
N-methyl-N-[2-[4-(methylsulfanyl)phenoxy]-5-(1H-1,2,3-triazol-1-yl)benzyl]amine;
N-methyl-N-[2-[4-(methylsulfanyl)phenoxy]-5-(1H-1,2,4-triazol-1-yl)benzyl]amine;
N,N-dimethyl-N-[2-[4-(methylsulfanyl)phenoxy]-5-(1H-1,2,4-triazol-1-yl)benzyl]-amine;
N-[2-[4-(methylsulfanyl)phenoxy]-5-(4H-1,2,4-triazol-4-yl)benzyl]-N,N-dimethylamine; and
N-{5-(3-amino-1H-pyrazol-1-yl)-2-[4-(methylsulfanyl)phenoxy]benzyl}-N-methylamine.
The compounds of the invention have the advantage that they are selective inhibitors of the re-uptake of serotonin (SRIs) (and so are likely to have reduced side effects), they have a rapid onset of action (making them suitable for administration shortly before an effect is required), they have desirable potency and associated properties. Compounds that selectively inhibit the re-uptake of serotonin, but not noradrenaline or dopamine, are preferred.
We have found that compounds of formula I which possess these properties have a relatively polar group at R4/R5. Therefore according to a further aspect, the invention provides a compound of general formula I and pharmaceutically acceptable salts thereof, wherein R1, R2, R3 and n are as defined in the first aspect; and R4 and R5, which may be the same or different, are xe2x80x94(CH2)pxe2x80x94Axe2x80x2, wherein p is 0, 1 or 2 and Axe2x80x2 is a polar group. In this aspect, polar groups may be defined as those having a negative xcfx80-value (see C Hansch and A Leo, xe2x80x98Substituent Constants for Correlation Analysis in Chemistry and Biologyxe2x80x99, Wiley, N.Y., 1979). In this system, H has a xcfx80-value of 0.00, xe2x80x94OCH3 has a xcfx80-value of xe2x88x920.02, and xe2x80x94SO2NH2 has a xcfx80-value of xe2x88x921.82, for example [see Table VI-I, xe2x80x98Well-Characterized Aromatic Substituentsxe2x80x99, p 49, ibid]. More preferred polar groups have a more negative xcfx80-value: thus, preferred groups have xcfx80-values of a greater negative value than xe2x88x920.1, more preferably a greater negative value than xe2x88x920.5, and most preferably a greater negative value than xe2x88x921.0. Even when p is other than zero in the above definition, the definition of Axe2x80x2 is based on the above reference as if p was zero.
The pharmaceutically or veterinarily acceptable salts of the compounds of the invention which contain a basic centre are, for example, non-toxic acid addition salts formed with inorganic acids such as hydrochloric, hydrobromic, hydroiodic, sulfuric and phosphoric acid, with carboxylic acids or with organo-sulfonic acids. Examples include the HCI, HBr, HI, sulfate or bisulfate, nitrate, phosphate or hydrogen phosphate, acetate, benzoate, succinate, saccharate, fumarate, maleate, lactate, citrate, tartrate, gluconate, camsylate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate and pamoate salts. Compounds of the invention can also provide pharmaceutically or veterinarily acceptable metal salts, in particular non-toxic alkali and alkaline earth metal salts, with bases. Examples include the sodium, potassium, aluminium, calcium, magnesium, zinc and diethanolamine salts. For reviews on suitable pharmaceutical salts see Berge et al, J. Pharm, Sci., 66, 1-19, 1977; Bighley et al, International Journal of Pharmaceutics, 33 (1986), 201-217; and P L Gould, Encyclopedia of Pharmaceutical Technology, Miarcel Debker Inc, New York 1996, Volume 13, page 453-497.
The pharmaceutically acceptable solvates of the compounds of the invention include the hydrates thereof.
Also included within the scope of the compound and various salts of the invention are polymorphs thereof.
Preferred salts are the tartrate salts, particularly the L-tartrate and the D-tartrate salts (and also the racemic D/L-tartrate); the phosphate salt; the hydrochloride salt; the citrate salt; and the sulfate salt. A further preferred salt is the sodium salt (see Example 28).
Hereinafter compounds, their pharmaceutically acceptable salts, their solvates or polymorphs, defined in any aspect of the invention (except intermediate compounds in chemical processes) are referred to as xe2x80x9ccompounds of the inventionxe2x80x9d.
The compounds of the invention may possess one or more chiral centres and so exist in a number of stereoisomeric forms. All stereoisomers and mixtures thereof are included in the scope of the present invention. Racemic compounds may either be separated using preparative HPLC and a column with a chiral stationary phase or resolved to yield individual enantiomers utilising methods known to those skilled in the art. In addition, chiral intermediate compounds may be resolved and used to prepare chiral compounds of the invention.
The compounds of the invention may exist in one or more tautomeric forms. All tautomers and mixtures thereof are included in the scope of the present invention. For example, a claim to 2-hydroxypyridinyl would also cover its tautomeric form, (xcex1-pyridonyl.
The invention also includes radiolabelled compounds. It will be appreciated by those skilled in the art that certain protected derivatives of compounds of the invention, which may be made prior to a final deprotection stage, may not possess pharmacological activity as such, but may, in certain instances, be administered orally or parenterally and thereafter metabolised in the body to form compounds of the invention which are pharmacologically active. Such derivatives may therefore be described as xe2x80x9cprodrugsxe2x80x9d. Further, certain compounds of the invention may act as prodrugs of other compounds of the invention.
All protected derivatives and prodrugs of compounds of the invention are included within the scope of the invention. Examples of suitable pro-drugs for the compounds of the present invention are described in Drugs of Today, Volume 19, Number 9, 1983, pp 499-538 and in Topics in Chemistry, Chapter 31, pp 306-316 and in xe2x80x9cDesign of Prodrugsxe2x80x9c by H. Bundgaard, Elsevier, 1985, Chapter 1 (the disclosures in which documents are incorporated herein by reference).
It will further be appreciated by those skilled in the art, that certain moieties, known to those skilled in the art as xe2x80x9cpro-moietiesxe2x80x9d, for example as described by H. Bundgaard in xe2x80x9cDesign of Prodrugsxe2x80x9d (the disclosure in which document is incorporated herein by reference) may be placed on appropriate functionalities when such functionalities are present within compounds of the invention.
Preferred prodrugs for compounds of the invention include : esters, carbonate esters, hemi-esters, phosphate esters, nitro esters, sulfate esters, sulfoxides, amides, carbamates, azo-compounds, phosphamides, glycosides, ethers, acetals and ketals.
Compounds of the invention may be prepared, in known manner in a variety of ways.
In the following reaction schemes and hereafter, unless otherwise stated, R1 to R13, n, m and p are as defined in the first aspect. These processes form further aspects of the invention
Throughout the specification, general formulae are designated by Roman numerals I, II, III, IV etc. Subsets of these general formulae are defined as Ia, Ib, Ic etc., . . . IVa, IVb, IVc etc.
Compounds of general formula (I) may be prepared from compounds of general formula (II) by a variety of methodologies (see Scheme 1), wherein L is a suitable leaving group such as halogen (F, Cl, Br or I) or a sulfonate ester such as trifluoromethanesulfonate or methanesulfonate, preferably L is F or Cl. 
For example:
i) Where R4/R5 are halogen, by reaction of (II) with a suitable halogenating agent in an inert solvent which does not adversely affect the reaction. Suitable halogenating agents include trifluoromethanesulfonic acid and N-iodosuccinimide and suitable inert solvents include dichloromethane as illustrated in Example 16 herein;
ii) Where R4/R5 are xe2x80x94NO2, by reaction of (II) with a suitable nitrating agent, such as an alkali metal nitrate, in an inert solvent which does not adversely affect the reaction at, or below, room temperature. Suitable nitrating agents include trifluoromethanesulfonic acid/ potassium nitrate and suitable inert solvents include trifluoroacetic acid, as illustrated in Example 21 herein; or
iii) Transformation to the compounds of formula I where R4/R5 is xe2x80x94SO2NR6R7 by reaction of an intermediate sulfonyl chloride with the requisite amine of formula HNR6R7 in a suitable solvent. Suitable solvents include ethanol and the reactions are generally performed at or below room temperature. For example, compounds of formula (la), where R5 is xe2x80x94SO2NR6R7, may be prepared via the intermediate sulfonyl chlorides (XII) from compounds of formula (II) by reaction of (II) with chlorosulfonic acid followed by reaction with HNR6R7. Reaction conditions typically comprise low temperature. The reaction can take place either neat, i.e. in the absence of solvent, or in the presence of an inert solvent which does not adversely affect the reaction. Suitable inert solvents include dichloromethane and a typical reaction temperature is 0xc2x0 C., as illustrated in Example 28 herein. The intermediate sulfonyl chloride (XII) may be isolated, purified and then reacted with HNR6R7, alternatively it may be generated in situ, without isolation, and then reacted with HNR6R7. 
Thus according to a further aspect, the invention provides a process for preparing compounds of general formula (I) from compounds of the general formula (II). In a preferred embodiment, there is provided a process for preparing compounds of formula (Ia) by reacting compounds of formula (II) in a suitable solvent, with chlorosulfonic acid to give compounds of formula (XII) followed by reaction with HNR6R7 to give compounds of formula (Ia). Preferably compounds of formula (XII) are generated in situ and reacted with HNR6R7 without isolation.
Compounds of general formula (II) may in turn be prepared from compounds of formula (III) by reaction with an amine of general formula HNR1R2, or with a suitable salt form thereof, together with a hydride reducing agent in a suitable solvent. When either R1 or R2 is hydrogen, suitable solvents include protic solvents such as ethanol, and sodium borohydride is an appropriate reducing agent. When neither R1 or R2 are hydrogen, tetrahydrofuran/dichloromethane is a suitable solvent system and sodium tri(acetoxy)borohydride is a suitable reducing agent. In such reactions the use of a salt form of HNR1R2, such as the hydrochloride is preferable, and an auxiliary base, to aid solubility of the HNR1R2 salt, such as triethylamine may optionally be added.
Compounds of formula (III) may be prepared in turn from the coupling of compounds of general formula (IV) with aldehyde compounds of general formula (V). Such coupling reaction may be accomplished by techniques known in the art, such as, via reaction with potassium carbonate in a suitable solvent such as dimethylformamide under appropriate reaction conditions such as elevated temperature and in an inert atmosphere.
Alternatively, compounds of general formula (I) may be prepared from compounds of general formula (VII) (See Scheme 2) in analogous fashion to the preparation of (II) (see Scheme 1). 
Compounds of general formula (VII) may be prepared from (VI) and (IV) in an analogous fashion to the preparation of (Ill) (see Scheme 1).
Alternatively, compounds of general formula (I) having a particular R4/R5 substituent may be converted into other compounds of formula (I) using known techniques. For example:
i) When R4/R5 is halogen such as chloro, bromo or iodo, it may be converted to cyano via reaction with a cyanide salt in the presence of a Pd(0) or (II)catalyst in a high boiling solvent at elevated temperatures. Suitable Pd catalysts include palladium tetrakis(triphenylphosphine), suitable cyanide salts include Zn(CN)2 and suitable high boiling solvents which do not adversely affect the reaction include dimethylformamide as exemplified by Example 81 herein;
ii) When R4/R5 is halogen such as chloro, bromo or iodo, it may be converted to xe2x80x94CH2CN via an intermediate cyanoester. The intermediate cyanoesters are formed by reaction with an xcex1-cyanoacetate in the presence of a copper(I) salt and a base, in a high boiling solvent at elevated temperatures. Suitable xcex1-cyanoacetates include ethyl xcex1-cyanoacetate, suitable copper(I) salts include copper(I) bromide, suitable bases include potassium carbonate and suitable high boiling solvents include dimethylsulfoxide. The intermediate cyanoesters may then be hydrolysed and decarboxylated in one step by treatment with a hydroxide salt in a high boiling solvent at elevated temperatures. Suitable hydroxide salts include sodium hydroxide and suitable high boiling solvents include aqueous dioxan, as exemplified by Example 89 herein;
iii) When R4/R5 is halogen such as chloro, bromo or iodo, it may be converted to the corresponding sulfide xe2x80x94SR by treatment with an alkyl thiolate salt and a Pd(0) or (II)catalyst, in an inert high boiling solvent which does not adversely affect the reaction, at elevated temperatures. Suitable alkyl thiolate salts include sodium methanethiolate, suitable Pd catalysts include palladium tetrakis(triphenylphosphine) and suitable inert high boiling solvents include dimethylsulfoxide as exemplified by Example 141 herein;
iv) When R4/R5 is halogen such as chloro, bromo or iodo, it may be converted to the corresponding ester xe2x80x94CO2R by treatment with carbon monoxide at high pressure with a Pd(0) or (II) catalyst, in an alcohol solvent (ROH wherein R is C1-C4 alkyl), in the presence of a base at elevated temperatures. For example the reaction may be carried out at pressures in the region of about 100 p.s.i., whilst suitable Pd catalysts include palladium tetrakis(triphenylphosphine), suitable bases include triethylamine and suitable alcohol solvents include methanol as exemplified by Example 151 herein;
v) When R4/R5 is halogen such as iodo, it may be converted to the corresponding amide xe2x80x94CONR6R7 wherein R6 and R7 are as previously defined herein, by treatment with carbon monoxide, the corresponding amine of formula HNR6R7 and a Pd(0)catalyst in an inert solvent which does not adversely affect the reaction. Suitable catalysts include palladium tetrakis(triphenylphosphine) and suitable solvents include dimethylformamide. The reaction is preferably conducted at an elevated temperature and pressure, as exemplified by Example 100 herein;
vi) When R4/R5 is halogen such as chloro, bromo or iodo, it may be converted to xe2x80x94CH2CN by reaction with tributyl(cyanomethyl)stannane [according to M. Kosugi, M. Ishiguro, Y. Negishi, H. Sano, T. Migita, Chem. Lett., 1984, 1511-1512] and a Pd-catalyst in a suitable solvent at elevated temperatures. Suitable catalysts include bis(acetonitrile)dichloro-palladium(II) and suitable solvents include m-xylene, as exemplified by Example 88 herein;
vii) When R4/R5 is halogen such as bromo, it may be converted to a heterocyclic group, by treatment with copper powder and the desired heterocyclic compound together with a base. Suitable heterocyclic groups are defined herein before and include 1,2,3-triazoles, suitable bases include potassium carbonate and the reaction is preferably carried out at elevated temperatures as exemplified by Example 181 herein;
viii) When R4/R5 is halogen such as bromo, it may be converted to an xcex1,xcex2-unsaturated sulfonamide, by treatment with vinylsulfonamide, a Pd(0) or (II) catalyst and a suitable base, in an inert solvent which does not adversely affect the reaction, at elevated temperatures. Suitable Pd catalysts include palladium (II) acetate in the presence of tri(o-tolyl)phosphine, suitable bases include triethylamine and suitable inert solvents include acetonitrile as exemplified by Example 67 herein;
ix) When R4/R5 is halogen such as bromo, it may be converted to an xcex1,xcex2-unsaturated amide, by treatment with acrylamide, a Pd(0) or (II) catalyst and a suitable base, in an inert solvent which does not adversely affect the reaction, at elevated temperatures. Suitable Pd catalysts include palladium (II) acetate in the presence of tri(o-tolyl)phosphine, suitable bases include triethylamine and suitable inert solvents include acetonitrile as exemplified by Example 68 herein;
x) When R4/R5 is an xcex1,xcex2-unsaturated sulfonamide, it may be converted to xe2x80x94CH2CH2SO2NH2, by treatment with a suitable reducing agent at an appropriate temperature, in an inert solvent which does not adversely affect the reaction. Suitable reducing agents include tosyl hydrazide at elevated temperature and suitable inert solvents include toluene as exemplified by Example 71 herein;
xi) When R4/R5 is nitro, it may be reduced to the corresponding xe2x80x94NH2 group via treatment with a reducing agent in a protic solvent at, or above, room temperature. Suitable reducing agents include iron powder / calcium chloride, suitable protic solvents include aqueous ethanol and at a typical reaction temperature of from about 70xc2x0 C. to about 100xc2x0 C., preferably about 90xc2x0 C., as exemplified by Example 107 herein;
xii) When R4/R5 is xe2x80x94NH2, it may be converted to the corresponding xe2x80x94NHSO2R9 group by reaction with a sulfonylating agent in the presence of a base in an inert solvent which does not adversely affect the reaction at, or below, room temperature. Suitable sulfonylating agents include methanesulfonic anhydride, suitable bases include triethylamine and suitable inert solvents include tetrahydrofuran as exemplified by Example 114 herein;
xiii) When R4/R5 is xe2x80x94NH2, it may be converted to a triazole by treatment with Nxe2x80x2-[(dimethylamino)methylidene]-N,N-dimethylhydrazonoformamide and a suitable acid, in an inert solvent which does not adversely affect the reaction, at elevated temperature. Suitable acids include xcfx81-toluenesulfonic acid and suitable solvents include toluene as exemplified by Example 189 herein;
xiv) When R4/R5 is a xe2x80x94NHSO2R9 group, it may be converted to the corresponding xe2x80x94NR8SO2R9 group via treatment with an alkylating agent and a base in a suitable inert solvent. Examples of suitable alkylating agents include 2-bromoethanol, suitable bases include potassium carbonate and suitable inert solvents include acetonitrile, as exemplified by Example 122 herein;
xv) When R4/R5 is a sulfonamide, it may be converted to an acyl sulfonamide by treatment with an acylating agent and a base in a solvent which does not adversely affect the reaction. Suitable acylating agents include acetic anhydride, suitable bases include triethylamine and suitable solvents include dichloromethane as exemplified by Example 66 herein;
xvi) When R4/R5 is xe2x80x94CN, it may be converted to the corresponding aldehyde by treatment with a hydride reducing agent in an inert solvent which does not adversely affect the reaction. Examples of suitable reducing agents include lithium aluminium hydride and suitable inert solvents include tetrahydrofuran. Such reactions are preferably carried out at low temperature and in an inert atmosphere as exemplified by Example 157 herein;
xvii) When R4/R5 is a nitrile xe2x80x94CN, it may be converted to the corresponding xe2x80x94C(O)NH2 group by hydrolysis under basic, oxidative or acid conditions. Basic hydrolysis is preferably conducted with a hydroxide salt such as potassium hydroxide in a protic solvent such as t-butanol at elevated temperatures, as exemplified in Example 91 herein. Oxidative hydrolysis is preferably conducted with hydrogen peroxide in a polar solvent such as dimethylsulfoxide in the presence of a suitable base, such as potassium carbonate at, or below, room temperature, as exemplified by Example 90 herein. Acidic hydrolysis is preferably conducted with a strong acid, such as polyphosphoric acid, at elevated temperatures, as exemplified by Example 92 herein;
xviii) When R4/R5 is xe2x80x94CN, it may be reduced to the corresponding amine xe2x80x94CH2NH2 via treatment with a hydride reducing agent, such as lithium aluminium hydride as exemplified by Example 110 herein;
xix) When R4/R5 is xe2x80x94CHO, it may be reduced to the corresponding alcohol xe2x80x94CH2OH via treatment with a reducing agent in a suitable solvent. Examples of suitable reducing agents include sodium borohydride, and suitable solvents include ethanol as exemplified by Example 157 herein;
xx) When R4/R5 is, it may be converted to the corresponding sulfoxide xe2x80x94S(O)R9 via low temperature treatment with an oxidising agent such as oxone (RTM) or hydrogen peroxide in a protic solvent as exemplified by Examples 145 or 149 herein;
xxi) When R4/ R5 is xe2x80x94SR10, it may be converted to the corresponding sulfone xe2x80x94SO2R10 via low temperature treatment with an oxidising agent such as oxone (RTM) or hydrogen peroxide in a protic solvent as exemplified by Examples 146 and 150 herein;
xxii) When R4/R5 is an ester, it may be reduced to the corresponding alcohol group xe2x80x94CH2OH via treatment with a hydride reducing agent, such as lithium aluminium hydride, as exemplified by Example 154 herein;
xxiii) When R4/R5 is an ester, it may be converted to the corresponding acid xe2x80x94CO2H by treatment with a suitable hydroxide salt in the presence of water and a suitable co-solvent. Suitable hydroxide salts include lithium hydroxide and suitable co-solvents include tetrahydrofuran, as exemplified by Example 158 herein; and
xxiv) When R4/R5 is a carboxylic acid, it may be converted to the corresponding amide xe2x80x94CONR6R7 by treatment with a coupling agent, a base and an amine HNR6R7 in a suitable inert solvent which does not adversely affect the reaction. Suitable coupling agents include 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in the presence of 1-hydroxybenzotriazole, suitable bases include triethylamine and suitable solvents include dichloromethane as exemplified by Example 159 herein.
Alternatively, compounds of general formula (I) having a particular NR1R2 group may be converted into compounds of general formula (I) having a different NR1R2 group. For example:
i) compounds of formula (I) wherein either R1 or R2 is hydrogen, can be converted into other compounds of formula (I) wherein neither R1 nor R2 are hydrogen, by reaction of the compound of formula (I) with an aldehyde and a hydride reducing agent. Suitable aldehydes include formaldehyde, suitable reducing agents include sodium tri(acetoxy)borohydride and the reaction is preferably conducted in a solvent which does not interfere with the reaction, such as dichloromethane at or below room temperature, as exemplified by Example 183 herein; and
ii) compounds of formula (I) wherein R1 is hydrogen, can be converted into other compounds of formula (I) wherein R1 is methyl, by reaction of the compound of formula (I) with a formylating agent in a suitable solvent, followed by subsequent reduction of the intermediate N-formyl compound with a hydride reducing agent in an inert solvent, preferably at elevated temperature. Suitable formylating agents include pentafluorophenyl formate (formed from formic acid, pentafluorophenol and dicyclohexylcarbodiimide) and suitable solvents for the formylation include dichloromethane. Suitable reducing agents include borane-tetrahydrofuran complex and suitable inert solvents for the reduction include tetrahydrofuran as exemplified by Example 128 herein.
Alternatively, compounds of general formula (I) may be prepared from compounds of formula (VIII) (see Scheme 3) wherein L is as defined for Scheme 1 and T is a group which can be converted into CH2NR1R2. Examples of suitable T substituents include: carboxy, alkoxycarbonyl, xe2x80x94CN and xe2x80x94C(O)NR1R2. 
Methodologies for converting compounds of formula (VIII) to (I), include:
i) where T is carboxy or alkoxycarbonyl, by reaction with an amine of general formula NHR1R2 to form an amide followed by reduction of the amide to provide a compound of formula (I). Such compounds of general formula (I) may be further reacted with a suitable aldehyde and hydride reducing agent, or a formylating agent followed by a hydride reducing agent, to provide a compound of formula (I);
ii) where T is xe2x80x94CN, by reduction to its corresponding amine of formula xe2x80x94CH2NH2. To provide further compounds of general formula (I), wherein either one or both of R1 or R2 are not hydrogen, the amine can be further reacted with a suitable aldehyde and hydride reducing agent, or a formylating agent followed by a hydride reducing agent, to provide a compound of formula (I); and
iii) where T is xe2x80x94C(O)NR1R2, by reduction to provide an amine followed optionally by an appropriate conversion of R1 and/or R2 if either is hydrogen into alternative R1 and/or R2 groups via treatment with aldehyde with subsequent reduction, or by treatment with a formylating agent followed by a hydride reducing agent.
Compounds of general formula (VIII) may be prepared in turn by the coupling of compounds of general formula (IX) and compounds of the general formula (IV). Reagents and conditions for such coupling reactions are as previously defined for the coupling of compounds of general formulae (IV) and (V) in Scheme 1.
Compounds of general formula (IX) may be prepared in turn from compounds of general formula (X) (see Scheme 4). 
Compounds of formula (IX) may be prepared by aromatic electrophilic substitution of compounds of formula (X) to give compounds of formula IX directly. Alternatively compounds of formula (IX) may be prepared in two or more steps; aromatic electrophillic substitution of compounds of formula (X) to give intermediate compounds which then undergo further reaction to give compounds of formula (IX). The intermediate compounds may be isolated or generated in sitiu without isolation. A preferred route is shown in Scheme 5. 
Compounds of formula (X) are reacted with sulfonyl chloride to give compounds of formula (Xl) followed by reaction with NHR6R7 to give compounds of formula (IXa).
A preferred route to compounds of formula (Ia) is shown in Scheme 6. Preferred reaction conditions for the final step involving reduction of compounds of formula (VIIIa) to compounds of formula (Ia), are treatment with borane-tetrahydrofuran complex (see Example 61.) 
According to further aspects, the invention provides compounds to formulae (II), (III), (VII), (VIII), (VIIIa) and (XII) as defined above. In compounds of general formula (II) when R1 and R2are methyl, and n is 1, R3 is not a xe2x80x94SMe group para to the ether linkage linking rings A and B.
Compounds of formulae (IV), (V), (VI) or (IX) are either known and available from commercial sources or are available from commercially available materials using known techniques.
It will be apparent to those skilled in the art that sensitive functional groups may need to be protected and deprotected during synthesis of a compound of formula I. This may be achieved by conventional techniques, for example as described in xe2x80x98Protective Groups in Organic Synthesisxe2x80x99, 3rd edition, by T W Greene and P G M Wuts, John Wiley and Sons Inc, 1999. Example 121 provides an example of a protecting group strategy employed in the synthesis of a compound of the present invention.
The skilled chemist will appreciate that diaryl ethers may be prepared using a number of synthetic methodologies. For a review of methodologies see J S Sawyer, Tetrahedron, 56 (2000) 5045-5065, incorporated herein by reference.
The compounds of the invention are useful because they have pharmacological activity in mammals, including humans. More particularly, they are useful in the treatment or prevention of a disorder in which the regulation of monoamine transporter function is implicated. Disease states that may be mentioned include hypertension, depression (e.g. depression in cancer patients, depression in Parkinson""s patients, postmyocardial infarction depression, subsyndromal symptomatic depression, depression in infertile women, paediatric depression, major depression, single episode depression, recurrent depression, child abuse induced depression, post partum depression and grumpy old man syndrome), generalized anxiety disorder, phobias (e.g. agoraphobia, social phobia and simple phobias), posttraumatic stress syndrome, avoidant personality disorder, premature ejaculation, eating disorders (e.g. anorexia nervosa and bulimia nervosa), obesity, chemical dependencies (e.g. addictions to alcohol, cocaine, heroin, phenobarbital, nicotine and benzodiazepines), cluster headache, migraine, pain, Alzheimers disease, obsessive-compulsive disorder, panic disorder, memory disorders (e.g. dementia, amnestic disorders, and age-related cognitive decline (ARCD)), Parkinson""s diseases (e.g. dementia in Parkinson""s disease, neuroleptic-induced parkinsonism and tardive dyskinesias), endocrine disorders (e.g. hyperprolactinaemia), vasospasm (particularly in the cerebral vasculature), cerebellar ataxia, gastrointestinal tract disorders (involving changes in motility and secretion), negative symptoms of schizophrenia, premenstrual syndrome, fibromyalgia syndrome, stress incontinence, Tourettes syndrome, trichotillomania, kleptomania, male impotence, attention deficit hyperactivity disorder (ADHD), chronic paroxysmal hemicrania, headache (associated with vascular disorders), emotional lability, pathological crying, sleeping disorder (cataplexy) and shock.
Disorders of particular interest include depression, attention deficit hyperactivity disorder, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse disorders and sexual dysfunction including (in particular) premature ejaculation. Premature ejaculation may be defined as persistent or recurrent ejaculation before, upon or shortly after penile penetration of a sexual partner. It may also be defined as ejaculation occurring before the individual wishes [see xe2x80x98The Merck Manualxe2x80x99, 16th edition, p 1576, published by Merck Research Laboratories, 1992].
Thus, according to further aspects, the invention provides:
i) a compound of formula (I), as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, for use as a pharmaceutical;
ii) the use of a compound of formula (I), as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, in the manufacture of a medicament for the treatment or prevention of a disorder in which the regulation of monoamine transporter function is implicated, for example depression, attention deficit hyperactivity disorder, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse disorders or sexual dysfunction including premature ejaculation;
iii) the use of a compound of general formula (I) as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, in the manufacture of a medicament for the treatment or prevention of premature ejaculation, and also provides a method of treatment or prevention of premature ejaculation comprising the administration of this compound to a patient in need of such treatment or prevention;
iv) a method of treatment or prevention of depression, attention deficit hyperactivity disorder, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse disorders or sexual dysfunction including premature ejaculation, which comprises administering a therapeutically effective amount of a compound of formula (I), as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, to a patient in need of such treatment or prevention;
v) a method of increasing ejaculatory latency which comprises the administration of an effective amount of a compound of formula (I), as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, to a male desiring increased ejaculatory latency; and
vi) a compound of formula (I), as defined in the first aspect, or pharmaceutically acceptable salts, solvates or polymorphs thereof, for the treatment or prevention of a disorder in which the regulation of monoamine transporter function is implicated, for example depression, attention deficit hyperactivity disorder, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse disorders or sexual dysfunction including premature ejaculation.
It is to be appreciated that all references herein to treatment include curative, palliative and prophylactic treatment.
The compounds of the invention may be administered alone or as part of a combination therapy. If a combination of active agents are administered, then they may be administered simultaneously, separately or sequentially. In particular, the compounds of the invention may be combined with the following for the treatment of premature ejaculation:
Alpha-blockers (e.g. phentolamine, doxazasim, tansulosin, terazasin, prazasin and Example 19 of WO9830560;
Apomorphine xe2x80x94teachings on the use of apomorphine as a pharmaceutical may be found in U.S. Pat. No. 5,945,117;
Dopamine D2 agonists (e.g. Premiprixal, Pharmacia Upjohn compound number PNU95666);
Melanocortin receptor agonists (e.g. Melanotan II);
PGE1 receptor agonists (e.g. alprostadil);
Mono amine transport inhibitors, particularly Noradrenaline Re-uptake Inhibitors (NRIs) (e.g. Reboxetine), other Serotonin Re-uptake Inhibitors (SRIs) (e.g. paroxetine) or Dopamine Re-uptake Inhibitors (DRIs);
5-HT3 antagonists (e.g. ondansetron and granisetron); and
PDE inhibitors such as PDE2 (e.g. erythro-9-(2-hydroxyl-3-nonyl)-adenine) and Example 100 of EP 0771799-incorporated herein by reference) and in particular a PDE5 inhibitor (e.g. sildenafil, 1-{[3-(3,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5, 1-f]-as-trazin-2-yl)-4-ethoxyphenyl]sulfonyl}-4-ethylpiperazine i.e. vardenafil / Bayer BA 38-9456) and IC351 (see structure below, Icos Lilly). 
For human use the compounds of the invention can be administered alone but in human therapy will generally be administered in admixture with a suitable pharmaceutical excipient, diluent or carrier selected with regard to the intended route of administration and standard pharmaceutical practice.
For example, the compounds of the invention, can be administered orally, buccally or sublingually in the form of tablets, capsules (including soft gel capsules), ovules, elixirs, solutions or suspensions, which may contain flavouring or colouring agents, for immediate-, delayed-, modified-, sustained-, dual-, controlled-release or pulsatile delivery applications. The compounds of the invention may also be administered via intracavernosal injection. The compounds of the invention may also be administered via fast dispersing or fast dissolving dosage forms.
Such tablets may contain excipients such as microcrystalline cellulose, lactose, sodium citrate, calcium carbonate, dibasic calcium phosphate, glycine, and starch (preferably corn, potato or tapioca starch), disintegrants such as sodium starch glycolate, croscarmellose sodium and certain complex silicates, and granulation binders such as polyvinylpyrrolidone, hydroxypropylmethylcellulose (HPMC), hydroxypropylcellulose (HPC), sucrose, gelatin and acacia. Additionally, lubricating agents such as magnesium stearate, stearic acid, glyceryl behenate and talc may be included.
Solid compositions of a similar type may also be employed as fillers in gelatin capsules. Preferred excipients in this regard include lactose, starch, a cellulose, milk sugar or high molecular weight polyethylene glycols. For aqueous suspensions and/or elixirs, the compounds of the invention, and their pharmaceutically acceptable salts, may be combined with various sweetening or flavouring agents, colouring matter or dyes, with emulsifying and/or suspending agents and with diluents such as water, ethanol, propylene glycol and glycerin, and combinations thereof.
Modified release and pulsatile release dosage forms may contain excipients such as those detailed for immediate release dosage forms together with additional excipients that act as release rate modifiers, these being coated on and/or included in the body of the device. Release rate modifiers include, but are not exclusively limited to, hydroxypropylmethyl cellulose, methyl cellulose, sodium carboxymethylcellulose, ethyl cellulose, cellulose acetate, polyethylene oxide, Xanthan gum, Carbomer, ammonio methacrylate copolymer, hydrogenated castor oil, carnauba wax, paraffin wax, cellulose acetate phthalate, hydroxypropylmethyl cellulose phthalate, methacrylic acid copolymer and mixtures thereof. Modified release and pulsatile release dosage forms may contain one or a combination of release rate modifying excipients. Release rate modifying excipients may be present both within the dosage form i.e. within the matrix, and/or on the dosage form, i.e. upon the surface or coating.
Fast dispersing or dissolving dosage formulations (FDDFs) may contain the following ingredients: aspartame, acesulfame potassium, citric acid, croscarmellose sodium, crospovidone, diascorbic acid, ethyl acrylate, ethyl cellulose, gelatin, hydroxypropylmethyl cellulose, magnesium stearate, mannitol, methyl methacrylate, mint flavouring, polyethylene glycol, fumed silica, silicon dioxide, sodium starch glycolate, sodium stearyl fumarate, sorbitol, xylitol. The terms dispersing or dissolving as used herein to describe FDDFs are dependent upon the solubility of the drug substance used i.e. where the drug substance is insoluble a fast dispersing dosage form can be prepared and where the drug substance is soluble a fast dissolving dosage form can be prepared.
The compounds of the invention can also be administered parenterally, for example, intravenously, intra-arterially, intraperitoneally, intrathecally, intraventricularly, intraurethrally, intrasternally, intracranially, intramuscularly or subcutaneously, or they may be administered by infusion techniques. For such parenteral administration they are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic with blood. The aqueous solutions should be suitably buffered (preferably to a pH of from 3 to 9), if necessary. The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques well known to those skilled in the art.
For oral and parenteral administration to human patients, the daily dosage level of the compounds of the invention or salts or solvates thereof will usually be from 10 to 500 mg (in single or divided doses).
Thus, for example, tablets or capsules of the compounds of the invention or salts or solvates thereof may contain from 2.5 mg to 250 mg of active compound for administration singly or two or more at a time, as appropriate. The physician in any event will determine the actual dosage which will be most suitable for any individual patient and it will vary with the age, weight and response of the particular patient. The above dosages are exemplary of the average case. There can, of course, be individual instances where higher or lower dosage ranges are merited and such are within the scope of this invention. The skilled person will also appreciate that, in the treatment of certain conditions (including PE), compounds of the invention may be taken as a single dose on an xe2x80x9cas requiredxe2x80x9d basis (i.e. as needed or desired).
In general a tablet formulation could typically contain between about 0.01 mg and 500 mg of a compound according to the present invention (or a salt thereof) whilst tablet fill weights may range from 50 mg to 1000 mg. An example formulation for a 10 mg tablet is illustrated:
The compounds of the invention can also be administered intranasally or by inhalation and are conveniently delivered in the form of a dry powder inhaler or an aerosol spray presentation from a pressurised container, pump, spray or nebulizer with the use of a suitable propellant, e.g. dichlorodifluoromethane, trichlorofluoromethane, dichlorotetra- fluoro-ethane, a hydrofluoroalkane such as 1,1,1,2-tetrafluoroethane (HFA 134A [trade mark]) or 1,1,1,2,3,3,3-heptafluoropropane (HFA 227EA [trade mark]), carbon dioxide or other suitable gas. In the case of a pressurised aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. The pressurised container, pump, spray or nebulizer may contain a solution or suspension of the active compound, e.g. using a mixture of ethanol and the propellant as the solvent, which may additionally contain a lubricant, e.g. sorbitan trioleate. Capsules and cartridges (made, for example, from gelatin) for use in an inhaler or insufflator may be formulated to contain a powder mix of a compound of the invention and a suitable powder base such as lactose or starch.
Aerosol or dry powder formulations are preferably arranged so that each metered dose or xe2x80x9cpuffxe2x80x9d contains from 1 to 50 mg of a compound of the invention for delivery to the patient. The overall daily dose with an aerosol will be in the range of from 1 to 50 mg which may be administered in a single dose or, more usually, in divided doses throughout the day.
The compounds of the invention may also be formulated for delivery via an atomiser. Formulations for atomiser devices may contain the following ingredients as solubilisers, emulsifiers or suspending agents: water, ethanol, glycerol, propylene glycol, low molecular weight polyethylene glycols, sodium chloride, fluorocarbons, polyethylene glycol ethers, sorbitan trioleate, oleic acid.
Alternatively, the compounds of the invention can be administered in the form of a suppository or pessary, or they may be applied topically in the form of a gel, hydrogel, lotion, solution, cream, ointment or dusting powder. The compounds of the invention may also be dermally or transdermally administered, for example, by the use of a skin patch. They may also be administered by the ocular, pulmonary or rectal routes.
For ophthalmic use, the compounds can be formulated as micronized suspensions in isotonic, pH adjusted, sterile saline, or, preferably, as solutions in isotonic, pH adjusted, sterile saline, optionally in combination with a preservative such as a benzalkonium chloride. Alternatively, they may be formulated in an ointment such as petrolatum.
For application topically to the skin, the compounds of the invention can be formulated as a suitable ointment containing the active compound suspended or dissolved in, for example, a mixture with one or more of the following: mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene polyoxypropylene compound, emulsifying wax and water. Alternatively, they can be formulated as a suitable lotion or cream, suspended or dissolved in, for example, a mixture of one or more of the following: mineral oil, sorbitan monostearate, a polyethylene glycol, liquid paraffin, polysorbate 60, cetyl esters, wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water.
The compounds of the invention may also be used in combination with a cyclodextrin. Cyclodextrins are known to form inclusion and non-inclusion complexes with drug molecules. Formation of a drug-cyclodextrin complex may modify the solubility, dissolution rate, bioavailability and/or stability property of a drug molecule. Drug-cyclodextrin complexes are generally useful for most dosage forms and administration routes. As an alternative to direct complexation with the drug the cyclodextrin may be used as an auxiliary additive, e.g. as a carrier, diluent or solubiliser. Alpha-, beta- and gamma-cyclodextrins are most commonly used and suitable examples are described in WO-A-91/11172, WO-A-94/02518 and WO-A-98/55148.
For oral or parenteral administration to human patients the daily dosage levels of compounds of formula (I), and their pharmaceutically acceptable salts, will be from 0.01 to 30 mg/kg (in single or divided doses) and preferably will be in the range 0.01 to 5 mg/kg. Thus tablets will contain 1 mg to 0.4 g of compound for administration singly or two or more at a time, as appropriate. The physician will in any event determine the actual dosage which will be most suitable for any particular patient and it will vary with the age, weight and response of the particular patient. The above dosages are, of course only exemplary of the average case and there may be instances where higher or lower doses are merited, and such are within the scope of the invention.
Oral administration is preferred. Preferably, administration takes place shortly before an effect is required.
For veterinary use, a compound of the invention, or a veterinarily acceptable salt thereof, or a veterinarily acceptable solvate or pro-drug thereof, is administered as a suitably acceptable formulation in accordance with normal veterinary practice and the veterinary surgeon will determine the dosing regimen and route of administration which will be most appropriate for a particular animal.
Thus according to a further aspect, the invention provides a pharmaceutical formulation containing a compound of formula (i), as defined in the first aspect, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable adjuvant, diluent or carrier.
The invention is illustrated by the following non-limiting Examples in which the following abbreviations and definitions are used:
Where indicated, compounds were characterised as their hydrochloride salts. A typical procedure for formation of hydrochloride salts is given in Preparation 21. The procedure can be carried out with other solvents e.g. diethyl ether or DCM.
The powder X-ray diffraction (PXRD) patterns were determined using a Siemens D5000 powder X-ray diffractometer fitted with a theta-theta goniometer, automatic beam divergence slits, a secondary monochromator and a scintillation counter. The specimen was rotated whilst being irradiated with copper K-alpha1 X-rays (Wavelength=1.5046 Angstroms) filtered with a graphite monochromator (xcex=0.15405 nm) with the X-ray tube operated at 40 kV/40 mA. The main peaks (in degrees 2 xcex8) of the PXRD patterns for the various solid forms are illustrated.
Melting points were determined using a Perkin Elmer DSC7 at a heating rate of 20xc2x0 C./minute.